A method for producing lyocell staple fibers and lyocell staple fibers

Abstract

The application discloses a preparation method of lyocell staple fiber and the lyocell staple fiber, and the preparation method comprises the following steps: 1) preparing fiber filaments and cutting the fiber filaments into staple fibers; 2) spreading the staple fibers into a fiber web; and 3) carrying out a cross-linking reaction on the fiber web, and then unwebbing to obtain the lyocell staple fiber. In the application, bending points are formed on the fiber web, the cross-linking stage is carried out on the fiber web, and the fiber brittleness is improved; the additive used in the cross-linking stage can be uniformly distributed on the fiber web, the uniformity of the anti-fibrillation performance of the cross-linked fiber is ensured, the mechanical properties of the fiber are improved, and the cross-linking rate is relatively high; the dry strength of the lyocell staple fiber is 3.72-4.40 dtex / cN, when the fineness of the lyocell staple fiber is 1.3 dtex, the wet rubbing value is 730-810 times, that is, the mechanical properties of the lyocell staple fiber are excellent, and the anti-fibrillation performance is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fibers, in particular, to a preparation method of Lyocell staple fiber and Lyocell staple fiber. BACKGROUND

[0002] Lyocell fiber is a kind of cellulose fiber prepared by dry-jet wet spinning method with N-methyl morpholine-N-oxide (NMMO) as solvent. Lyocell fiber uses wood pulp, bamboo pulp and cotton pulp as raw materials, and the recovery rate of N-methyl morpholine-N-oxide (NMMO) reaches more than 99.5% during the preparation process, which is economically applicable and environmentally friendly, and has no pollution to the environment. Lyocell fiber has excellent mechanical properties and good moisture absorption, and has silk-like luster and soft hand feeling, and is known as "the most promising green fiber in the 21st century", and has been widely produced at home and abroad.

[0003] Lyocell fiber has high crystallinity and orientation, and is easy to absorb water and swell in a wet environment, so that the hydrogen bonds between fibrils are destroyed and the lateral bonding force is weakened. Therefore, under the action of mechanical force, the fibrils will separate from each other, and the fibrillation phenomenon will occur on the surface of the fiber. The fibrillation tendency of Lyocell fiber seriously limits the application of Lyocell fiber.

[0004] In order to improve the fibrillation problem of Lyocell fiber:

[0005] Patent CN1119030A uses polyethylene glycol as a crosslinking agent to prepare non-fibrillated Lyocell fiber, which has the disadvantage of high crosslinking temperature, which can easily damage the fiber;

[0006] Patent CN104005225A uses glyoxal as a crosslinking agent, magnesium chloride, aluminum sulfate and tartaric acid as catalysts. Glyoxal will volatilize into the air during production, which will pollute the environment;

[0007] Patents CN110924153A and CN113265788A use TAHT as a crosslinking agent and inorganic alkali as a catalyst, and use a mixed addition method of crosslinking agent and catalyst. The crosslinking agent will hydrolyze in the mixed solution, which is not conducive to the efficient use of the crosslinking agent, and the solidification time is long, which is not conducive to industrial production.

[0008] Therefore, the present application is proposed. SUMMARY

[0009] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a preparation method of Lyocell staple fiber to improve the utilization rate of crosslinking agent, enhance the mechanical properties of the fiber, avoid fiber brittleness and reduce the preparation cost.

[0010] The basic idea of the technical scheme of the present application is: a preparation method of lyocell staple fiber, comprising:

[0011] 1) preparing fiber filaments and cutting the fiber filaments into staple fibers;

[0012] 2) laying the staple fibers into a fiber web;

[0013] 3) after cross-linking reaction on the fiber web, the fiber web is disentangled to obtain lyocell staple fiber.

[0014] In the present application, the fiber web forms a bending point, and the cross-linking stage is carried out on the fiber web, which improves the fiber brittleness; the additives and cross-linking agents can be uniformly distributed on the fiber web, ensuring uniform anti-fibrillation performance of the cross-linked fibers, improving the mechanical properties of the fibers, and having a high cross-linking rate.

[0015] Further, the cross-linking reaction of step 3) comprises: applying cross-linking agents, salt agents, and alkali agents on the fiber web, and performing cross-linking reaction under heating conditions.

[0016] In the present application, the alkali agent provides an alkaline environment, so that the fiber is fully swollen, and the activity of the hydroxyl group in the cellulose fiber is increased. The salt agent can reduce the charge resistance between the cross-linking agent and the fiber, thereby improving the reaction efficiency of the cross-linking agent.

[0017] Further, the method of applying cross-linking agents, salt agents, and alkali agents comprises: first applying one or two of the cross-linking agents, salt agents, and alkali agents, and then applying the remaining one or two; or simultaneously applying the cross-linking agents, salt agents, and alkali agents.

[0018] Preferably, after applying the cross-linking agents, salt agents, and alkali agents, pressure is applied to the fiber web to press out the cross-linking agents, salt agents, and alkali agents; preferably, the pressure applied is in the range of 0.1 MPa to 10 MPa.

[0019] After the cross-linking agent or the salt agent or the alkali agent is subjected to a certain pressure, it can effectively and uniformly penetrate the fiber web, thereby improving the cross-linking rate of the fiber. The first applied cross-linking agent or salt agent or alkali agent can be pressed out for repeated use, which can effectively improve its utilization rate.

[0020] Different addition sequences of the cross-linking agent, the alkali agent, and the salt agent can all achieve the production of anti-fibrillation lyocell fibers under the present process.

[0021] Further, the cross-linking agent or the salt agent or the alkali agent is added cyclically 1-3 times, so that the cross-linking agent or the salt agent or the alkali agent is uniformly distributed on the fiber web, ensuring uniform anti-fibrillation performance of the cross-linked fibers, and having a high cross-linking rate.

[0022] Further, the temperature of the one or more of the cross-linking agent, the salt agent, and the alkali agent applied is controlled in the range of 10-95℃, preferably 65-95℃.

[0023] In the present application, the temperature of the cross-linking agent, the salt agent, and the alkali agent is controlled in the range of 65-95℃. When the temperature is greater than 65℃, the cross-linking agent can react with the cellulose fibers, so that a partial cross-linking reaction occurs before entering the reaction chamber, thereby reducing energy consumption.

[0024] Further, the temperature of the heating in the step 3) is 70-150℃, preferably 80-120℃.

[0025] Preferably, the heating in the step 3) is performed by one or more of radio frequency heating, microwave heating, oven heating, and steam heating, preferably radio frequency heating or steam heating.

[0026] Preferably, the heating in the step 3) is performed for 0.5-6min.

[0027] The heating in the step 3) is the first drying of the fibers, and is the only drying of the fibers, and all the previous treatments are performed in a wet state of the fibers.

[0028] Further, the fiber web is cleaned with a cleaning agent before the unwebbing in the step 3).

[0029] Preferably, the cleaning agent includes one or both of water and an acidic solution, preferably the acidic solution.

[0030] Preferably, the acidic solution includes one or more of acetic acid, hydrochloric acid, sulfuric acid, and oxalic acid.

[0031] Preferably, the concentration of the acidic solution is 0.005-1.5wt%.

[0032] In the present application, the fiber web is cleaned with a cleaning agent before the unwebbing, and then the fibers are cleaned with pure water. The use of the cleaning agent can neutralize the unreacted alkali agent on the fibers, and the fibers can be quickly cleaned and the waste discharge amount is small.

[0033] Further, the cross-linking agent is selected from triazine cross-linking agents, preferably 1,3,5-acrylamide hexahydro-1,3,5-triazine.

[0034] Preferably, the concentration of the cross-linking agent is in the range of 0.3-6wt%, preferably 0.5-3wt%.

[0035] Further, the alkali agent includes one or more of ammonia, sodium hydroxide, potassium hydroxide, phosphate, sodium bicarbonate, and sodium carbonate.

[0036] Preferably, the pH range of the alkali agent is 11-14; preferably, the pH range is 11.5-13.

[0037] Further, the salt agent is one or more of sodium chloride, sodium sulfate, potassium chloride, magnesium chloride, and phosphate;

[0038] Preferably, the concentration range of the salt agent is 0.5-6wt%, preferably 0.5-3wt%.

[0039] The present application also provides a lyocell staple fiber, the dry strength of the lyocell staple fiber being 3.97-4.08dtex / cN;

[0040] Preferably, when the fineness of the lyocell staple fiber is 1.3dtex, the wet rubbing value thereof is 780-810 times;

[0041] Preferably, the lyocell staple fiber is prepared by the preparation method according to any one of the above technical solutions.

[0042] After the above technical solution is adopted, the present application has the following beneficial effects compared with the prior art:

[0043] In the present application, the bending point is formed on the fiber web, the cross-linking stage is carried out on the fiber web, and the fiber brittleness is improved; the additive used in the cross-linking stage can be uniformly distributed on the fiber web, the uniformity of the anti-fibrillation performance of the cross-linked fiber is ensured, the mechanical properties of the fiber are improved, and the cross-linking rate is high.

[0044] In the present application, the alkali agent provides an alkaline environment, so that the fiber is fully swollen, and the activity of the hydroxyl group in the cellulose fiber is increased. The salt agent can reduce the charge resistance between the cross-linking agent and the fiber, thereby improving the reaction efficiency of the cross-linking agent.

[0045] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0046] The drawings are part of the present application, which are used to provide a further understanding of the present application, the schematic embodiments of the present application and the description thereof are used to explain the present application, but do not constitute an improper limitation on the present application. Obviously, the drawings described below are only some embodiments, and other drawings can be obtained by those skilled in the art without creating laborious work. In the drawings:

[0047] Figure 1 is a process flow chart of the present application.

[0048] It should be noted that these drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0049] Example 1

[0050] 1) Cut the filament dissolved and formed in N-methylmorpholine-N-oxide (NMMO) into short fibers of 38 mm,

[0051] 2) Lay the short fibers into a fiber web;

[0052] 3) Add a crosslinking agent (1,3,5-acrylamidohexahydro-1,3,5-triazine) solution of 2.5 wt% at a temperature of 80°C, pad three times, recycle the crosslinking agent solution while supplementing the crosslinking agent to maintain the concentration of the crosslinking agent solution, and then add an alkali agent (sodium hydroxide and sodium carbonate) of pH 12 and a salt agent (sodium sulfate 2 wt% and sodium chloride 2 wt%) at a temperature of 80°C, pad three times, with a press roll pressure of 0.2 MPa, heat the fiber web at 100°C for 6 min, clean the fiber web with a 0.01% hydrochloric acid solution, then clean the fiber web with pure water until neutral, and then prepare Lyocell fibers with anti-fibrillation effect through oiling, opening, and drying.

[0053] Example 2

[0054] 1) Cut the filament dissolved and formed in N-methylmorpholine-N-oxide (NMMO) into short fibers of 38 mm,

[0055] 2) Lay the short fibers into a fiber web;

[0056] 3) Add an alkali agent (sodium hydroxide and sodium phosphate) of pH 13 and a salt agent (sodium sulfate 3 wt% and sodium chloride 3 wt%) at a temperature of 85°C, pad three times, recycle the alkali agent and the salt agent while supplementing a certain amount of the alkali agent and the salt agent to maintain the concentration of the alkali agent and the salt agent, and then add a crosslinking agent (1,3,5-acrylamidohexahydro-1,3,5-triazine) solution of 2.5 wt% at a temperature of 85°C, pad three times, with a press roll pressure of 0.2 MPa, heat the fiber web at 110°C for 2 min, clean the fiber with a 0.02% oxalic acid solution, then clean the fiber web with pure water until neutral, and then prepare Lyocell fibers with anti-fibrillation effect through oiling, opening, and drying.

[0057] Example 3

[0058] 1) Cut the filament dissolved and formed in N-methylmorpholine-N-oxide (NMMO) into short fibers of 38 mm,

[0059] 2) Lay the short fibers into a fiber web;

[0060] 3) adding a mixed solution of alkali agent (sodium phosphate and sodium carbonate) at 85°C and pH 11, salt agent (sodium chloride 3 wt%) and crosslinking agent (1,3,5-acrylamidohexahydro-1,3,5-triazine) at 2.5 wt% concentration, padding three times with a pressure roller pressure of 0.5 MPa, heating the web at 105°C for 4.5 min, washing the fiber with 0.03% acetic acid solution, then washing the web with pure water until neutral, then oiling, opening and drying to produce lyocell fiber with anti-fibrillation effect.

[0061] Example 4

[0062] 1) cutting the filament dissolved and formed in N-methylmorpholine-N-oxide (NMMO) into short fibers of 38 mm,

[0063] 2) laying the short fibers into a fiber web;

[0064] 3) adding alkali agent (sodium hydroxide and phosphoric acid) at 90°C and pH 13, padding three times, recycling the alkali agent while supplementing a certain amount of alkali agent to keep the solution pH constant, then adding crosslinking agent (1,3,5-acrylamidohexahydro-1,3,5-triazine) at 2.5 wt% concentration and salt agent (sodium sulfate 3 wt%), padding three times with a pressure roller pressure of 0.6 MPa, heating the web at 110°C for 4 min, washing the web with 0.02% oxalic acid solution, then washing the web with pure water until neutral, then oiling, opening and drying to produce lyocell fiber with anti-fibrillation effect.

[0065] Example 5

[0066] 1) cutting the filament dissolved and formed in N-methylmorpholine-N-oxide (NMMO) into short fibers of 38 mm,

[0067] 2) laying the short fibers into a fiber web;

[0068] 3) adding alkali agent (sodium hydroxide and phosphoric acid) at 90°C and pH 13, padding three times, recycling the alkali agent while supplementing a certain amount of alkali agent to keep the solution pH constant, then adding crosslinking agent (1,3,5-acrylamidohexahydro-1,3,5-triazine) at 2.5 wt% concentration and salt agent (sodium sulfate 3 wt%), padding three times with a pressure roller pressure of 0.6 MPa, heating the web at 110°C for 4 min, washing the web with 0.02% oxalic acid solution, then washing the web with pure water until neutral, then oiling, opening and drying to produce lyocell fiber with anti-fibrillation effect.

[0069] Example 6

[0070] 1) Dissolve and form the filament in N-methylmorpholine-N-oxide (NMMO) into short fibers of 38 mm,

[0071] 2) Lay the short fibers into a fiber web;

[0072] 3) Add an alkali agent (sodium hydroxide and sodium carbonate) with a temperature of 90°C and a pH of 13, pad three times, recycle the alkali agent while supplementing a certain amount of alkali agent to keep the pH of the alkali agent unchanged, and then add a cross-linking agent (1,3,5-acrylamide hexahydro-1,3,5-triazine) with a temperature of 90°C and a concentration of 2.5wt% and a salt agent (sodium chloride 2.5wt%), pad three times, with a pressure roller pressure of 0.6MPa, heat the fiber web at 100°C for 3min, clean the fiber web with a sulfuric acid solution with a concentration of 0.015%, and then clean the fiber web with pure water until neutral, and then prepare Lyocell fibers with anti-fibrillation effect through oiling, opening, and drying.

[0073] Example 7

[0074] The difference between this example and Example 6 is that in step 3), the fiber web is heated at 110°C for 3min.

[0075] Example 8

[0076] The difference between this example and Example 6 is that in step 3), the fiber web is heated at 120°C for 3min.

[0077] Example 9

[0078] The difference between this example and Example 6 is that in step 3), the fiber web is heated at 130°C for 3min.

[0079] Example 10

[0080] 1) Dissolve and form the filament in N-methylmorpholine-N-oxide (NMMO) into short fibers of 38 mm,

[0081] 2) Lay the short fibers into a fiber web;

[0082] 3) adding alkali agent (sodium phosphate and sodium carbonate) with a temperature of 85℃ and a pH of 12.5, padding three times, recycling the alkali agent while adding a certain amount of alkali agent to keep the pH of the alkali agent unchanged. Then adding cross-linking agent (1,3,5-acrylamide hexahydro-1,3,5-triazine) and salt solution (sodium sulfate 3wt%) with a concentration of 2.5wt% and a temperature of 85℃, padding three times, wherein the pressure roller pressure is 0.5MPa, the fiber web is heated at 100℃ for 0.5min, the fiber is cleaned with oxalic acid solution with a concentration of 0.02%, then the fiber is cleaned with pure water until neutral, then the fiber is oiled, opened and dried to prepare lyocell fiber with anti-fibrillation effect.

[0083] Example 11

[0084] The difference between this example and example 10 is only that in step 3), the fiber web is heated at 100℃ for 2min.

[0085] Example 12

[0086] The difference between this example and example 10 is only that in step 3), the fiber web is heated at 100℃ for 4min.

[0087] Test Example 1

[0088] The properties of the lyocell fibers obtained in examples 1-5 are detected in this test example, wherein the linear density is detected according to GB / T14335-2008; the dry breaking strength and the hooking elongation are detected according to GB / T14337-2008; the wet rubbing value is detected according to FZ / T52019-2018; the detection results are as shown in the following table 1:

[0089] Table 1

[0090]

[0091]

[0092] As can be seen from table 1, the dry breaking strength of the lyocell fibers prepared in examples 1-5 of the present application is 3.97-4.08dtex / cN, and the hooking elongation is 1.4-2.8%, that is, the mechanical properties of the lyocell fibers obtained by the preparation method of the present application are excellent. When the fineness of the lyocell staple fiber is 1.3dtex, the wet rubbing value is 780-810 times, that is, the lyocell fiber obtained by the preparation method of the present application has a higher wet rubbing value, indicating that the anti-fibrillation performance of the lyocell fiber is excellent.

[0093] Test Example 2

[0094] The properties of the lyocell fibers obtained in Examples 6 to 9 were detected in this test example, wherein the linear density was detected by GB / T14335-2008; the dry breaking strength and the hooking elongation were detected by GB / T14337-2008; the wet rubbing value was detected by FZ / T52019-2018; and the detection results are as shown in Table 2 below:

[0095] Table 2

[0096]

[0097] As can be seen from Table 2, when the temperature of the heated fiber web is in the range of 100-130℃, the wet rubbing value is relatively large, and the lyocell fiber has good anti-fibrillation performance. Further, the higher the temperature, the relatively worse the mechanical properties of the lyocell fiber will be, and therefore, it is necessary to control the temperature of the heated fiber web to be kept within a certain range.

[0098] Test Example 3

[0099] The properties of the lyocell fibers obtained in Examples 10 to 12 were detected in this test example, wherein the linear density was detected by GB / T14335-2008; the dry breaking strength and the hooking elongation were detected by GB / T14337-2008; the wet rubbing value was detected by FZ / T52019-2018; and the detection results are as shown in Table 3 below:

[0100] Table 3

[0101]

[0102] As can be seen from Table 3, when the heated fiber web is heated at 100℃ for 0.5-4min, the wet rubbing value is relatively large, and the lyocell fiber has good anti-fibrillation performance. Further, the longer the heating time, the relatively worse the mechanical properties and the wet rubbing value of the lyocell fiber will be, and therefore, it is necessary to control the heating time of the heated fiber web to be kept within a certain range.

[0103] Comparative Example 1

[0104] 1) Dissolving and forming filament fibers in N-methylmorpholine-N-oxide (NMMO),

[0105] 2) adding alkali agent (sodium hydroxide and phosphoric acid) with a temperature of 90°C and a pH of 13, padding three times, recycling the alkali agent while supplementing a certain amount of alkali agent to keep the pH of the solution unchanged, then adding cross-linking agent (1, 3, 5-acrylamide hexahydro-1, 3, 5-triazine) with a concentration of 2wt% and salt agent (sodium sulfate 3wt%) with a temperature of 85°C, padding three times, wherein the pressure roller pressure is 0.6MPa, heating the filament fiber at 110°C for 4min, cleaning the filament fiber with a 0.02% oxalic acid solution, then cleaning the filament fiber with pure water until neutral, then oiling, drying and cutting to prepare lyocell fiber with anti-fibrillation effect.

[0106] The properties of the lyocell fiber obtained in the present comparative example were detected, wherein the linear density was detected according to GB / T14335-2008; the dry breaking strength and the hooking elongation were detected according to GB / T14337-2008; the wet rubbing value was detected according to FZ / T52019-2018; and the detection results were compared with those of Example 5, and the results are shown in Table 4 below:

[0107] Table 4:

[0108]

[0109] As can be seen from the above table, by cutting the filament into short fibers, the wet rubbing value, the dry breaking strength and the hooking elongation of the lyocell fiber can be obviously improved, that is, by cutting the filament into short fibers to form bending points on the fiber web, the cross-linking stage is carried out on the fiber web, and the fiber brittleness is improved; the additives used in the cross-linking stage can be uniformly distributed on the fiber web, ensuring the uniformity of the anti-fibrillation performance of the cross-linked fiber and improving the mechanical properties of the fiber.

[0110] Comparative Example 2

[0111] 1) cutting the filament fiber dissolved and formed in N-methylmorpholine-N-oxide (NMMO),

[0112] 2) adding alkali agent (sodium hydroxide and phosphoric acid) with a temperature of 90°C and a pH of 13, padding three times, recycling the alkali agent while supplementing a certain amount of alkali agent to keep the pH of the solution unchanged, then adding cross-linking agent (1, 3, 5-acrylamide hexahydro-1, 3, 5-triazine) with a concentration of 2wt% and salt agent (sodium sulfate 3wt%) with a temperature of 85°C, padding three times, wherein the pressure roller pressure is 0.3MPa, heating the filament fiber at 110°C for 4min, cleaning the filament fiber with a 0.02% oxalic acid solution, then cleaning the filament fiber with pure water until neutral, then oiling, drying and cutting to prepare lyocell fiber with anti-fibrillation effect.

[0113] The properties of the lyocell fiber obtained from the present comparative example were detected, wherein the linear density was detected according to GB / T14335-2008; the dry breaking strength and the hooking elongation were detected according to GB / T14337-2008; the wet rubbing value was detected according to FZ / T52019-2018; and the detection results were compared with those of Example 5, and the results are shown in Table 5 below:

[0114] Table 5:

[0115]

[0116] From the above table, it can be seen that within a certain pressure range, the greater the pressure applied on the fiber web, the greater the corresponding wet rubbing value of the lyocell fiber, the higher the dry breaking strength, and the greater the hooking elongation, that is, increasing the pressure applied on the fiber web within a certain range is beneficial to improving the mechanical properties of the fiber.

[0117] The above description is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above-mentioned technical content without departing from the technical solution of the present application, and any simple modification, equivalent change and modification of the above-mentioned embodiment according to the technical essence of the present application still belong to the scope of the present application.

Claims

1. A method for preparing lyocell short fibers, characterized in that: 1) Prepare fiber filaments and cut the fiber filaments into short fibers; 2) Lay the short fibers into a fiber web; 3) Apply one or two of the following crosslinking agents, salts, and alkalis to the fiber web at a temperature controlled within the range of 65-95℃, followed by the application of the remaining one or two. After each application of one or two of the crosslinking agents, salts, and alkalis, the fiber web is impregnated three times. The pressure of the rollers during impregnation is 0.1MPa-2MPa. Replenish the previously applied crosslinking agent, salt, or alkali, maintaining the concentration of the previously applied crosslinking agent, salt, or alkali at the same level, and then apply the remaining one or two. The crosslinking agent and alkali are not applied simultaneously. The pH range of the alkali is 11-14, the concentration range of the salt is 0.5-6wt%, and the concentration range of the crosslinking agent is 0.3-6wt%. Then, carry out the crosslinking reaction under radio frequency heating conditions at a temperature of 70-150℃, which is higher than the temperature of the crosslinking agent, salt, and alkali, for a heating time of 0.5-6 minutes. After the crosslinking reaction, the fibers are cleaned with an acidic solution with a concentration of 0.005-1.5wt%, and then the fiber web is cleaned with pure water until neutral. After that, the web is unwound to obtain lyocell short fibers with a dry strength of 3.72-4.40 dtex / cN and a wet friction value of 730-810 cycles.

2. The method for preparing lyocell short fibers according to claim 1, characterized in that: The heating temperature in step 3) is 80-120℃.

3. The method for preparing lyocell short fibers according to claim 2, characterized in that: The crosslinking agent is selected from one or more of 1,3,5-acrylamidohexahydro-1,3,5-triazine, 2,4-diacrylamidobenzenesulfonic acid, and N,N-methylenediacrylamide.

4. The method for preparing lyocell short fibers according to claim 3, characterized in that: The crosslinking agent is selected from 1,3,5-acrylamidohexahydro-1,3,5-triazine.

5. The method for preparing lyocell short fibers according to claim 4, characterized in that: The concentration range of the crosslinking agent is 0.5-3 wt%.

6. A method for preparing lyocell staple fiber according to any one of claims 1-5, characterized in that: The alkaline agent includes one or more of ammonia, sodium hydroxide, potassium hydroxide, phosphate, sodium bicarbonate, and sodium carbonate.

7. The method for preparing lyocell short fibers according to claim 6, characterized in that: The pH range of the alkaline agent is 11.5-13.

8. A method for preparing lyocell staple fiber according to any one of claims 1-5, characterized in that: The salting agent is one or more of sodium chloride, sodium sulfate, potassium chloride, magnesium chloride, and phosphate.

9. The method for preparing lyocell short fibers according to claim 8, characterized in that: The concentration range of the salt is 0.5-3 wt%.

10. A type of lyocell staple fiber, characterized in that: The lyocell short fibers are prepared using the preparation method described in any one of claims 1-9 above; When the fineness of lyocell short fibers is 1.3 dtex, its wet friction value is 730-810 times.

Images